Following the manufacture and assembly of an electric machine, there are tolerances associated with the inductance and back emf of the electric machine. For example, tolerances in the geometry of the stator pole tips as well as the air gap influence the inductance of the machine, while tolerances in the magnetic properties of the rotor and the geometry of the air gap influence the back emf. Consequently, electric machines manufactured and assembled using the same process may perform differently. In particular, the output power of the electric machines may differ.